The purpose of this research study is to test the experimental drug, SAR444245, in combination with other anticancer therapies, cetuximab or pembrolizumab, for the treatment of advanced or metastatic gastrointestinal cancer. SAR444245 will also be combined with one anticancer therapy, pembrolizumab, that belongs to a class of therapies called immune checkpoint inhibitors (ICI- type of drug that blocks proteins called checkpoints that are made by immune system cells and some cancer cells) that is already approved for the treatment of these conditions. Investigational means that the drug has...